Crazy ridiculous safety saw can detect fingers and shut off


I’m in awe of this SawStop safety saw. Basically, it has a fancy capacitance sensor in it, that can detect when the blade makes the slightest contact with a finger, and immediately stop it’s rotation and pull the blade out of reach. The standard safety arguments (potentially great benefit, but adds cost, complexity, possible complacency) probably apply here, but it sounds like a great idea- does anyone here have experience with them? [thanks, Doug!]

40 thoughts on “Crazy ridiculous safety saw can detect fingers and shut off

  1. nate_maker says:

    SawStops have been around for quite a few years now. The carpentry shop I work in at my college has these. They really do work! And it isn’t just a finger that they detect. Anything that will conduct an electrical current can trigger the brake.

  2. trevhar says:

    We had one at the place I worked last and it went off twice while I worked there. Didn’t witness the screeching, dropping halt, but both sawyers received the smallest and shallowest of little cuts on their fingers. It’s a great investment.

  3. Jim McCorison says:

    Yup, and if a false trip happens, you get to purchase a new SawStop cartridge (about $59) and a new saw blade (potential over $100). But the worst part, is that we may not have a chance to purchase a table saw without this technology in the future.

    In 2006 an untrained worker, using the saw without guards, and cross-cutting without a miter attachment (basically a recipe on how to injure yourself with a tablesaw) mutilated his hand. He was awarded $1.5 million because the manufacturer of the saw didn’t include SawStop technology in the saw.

    An increasing risk averse business environment means that there is a good likelihood that saw manufacturers will feel obligated to add this technology to their saws at the cost of $150 – $200 per saw. The inventory of SawStop is requiring 8% royalty to use his invention, an amount that is reported to be far in excess of the normal royalties paid.

    While a nice feature, it is extremely expensive. Yes, cheaper than a new hand, but when amortized across the millions of saws sold annually, the cost per injury makes the $1.5M award seem paltry. While genuine accidents do happen, the real end result of this is that tablesaw consumers will fund a device to reduce injuries of negligent and ill trained operators.

    1. Scooby says:

      It seems that the problem in that case wasn’t the lack of a SawStop; it was the “untrained worker”. Both are the fault of the employer, but only the lack of the SawStop allows for bringing in Ryobi as a co-defendant.

  4. xrcrguy says:

    We have a Saw Stop at my workplace that’s been under moderate usage for about a year now. Fortunately it’s only ever been triggered once and that was when a fellow didn’t put the sensor into override while cutting a sheet of aluminium. That saw blade and brake cartridge now hang on the wall of the shop and we point it out to all people not familiar with the operation of the saw. The saw we purchased for the shop is a professional quality cabinet saw, and yes, while it is a bit more expensive, if it saves us from one injury then it has more than paid for itself. I’ve seen what a 1/4″ dado blade can do to a man, and it can put him out of work for along time, if not permanently. I hope this becomes industry standard.

    You always hope that people that use equipment that can easily maim you are competent and safe, but it doesn’t always work out that way. This goes a long way towards making the table saw safe for all people.

  5. Jennifer Elaan says:

    I’ve had a chance to look at one in person, and I’m saving my pennies. It’s a well built saw, in addition to the safety systems.

    Still, there is one thing in the debate about the cost of licensing SawStop’s patents that’s been bothering me ever since I looked it up. US Patent #3785230, filed Nov 8, 1972. With such well-described prior art, the scope of SawStop’s patent is heavily restricted, and any company that wanted to make a similar system could invent their own system and market it without paying SawStop a dime.

    I’ve drawn up a few concepts for systems that don’t destroy the blade and don’t require consumable brake cartridges, but I don’t really have the resources to take them beyond the sketchbook stage, at this time.

  6. dokein says:

    I couldn’t help but notice the guy dipping his hand into a cooler full of saltwater first. Gotta wonder if it works quite so well with a dry hand covered in sawdust. Blood is conductive too, so I’m sure it will still stop, but they could be a painful couple of the extra milliseconds.

  7. netserv666 says:

    I have had one of these for about a year now and absolutely swear by it. It is a high end cabinet saw and as such it is competitively priced with the Delta Unisaw. Finewooding magazine and web site have written extensive reviews on both.
    I have a hundred dollar Makita contractor table saw as well it is fine for carpentry work although no safety … But for high end woodworking the Saw Stop is just amazing. I did have one “false” trigger but that was my fault ran some metal into it … that would have damaged the blade on a regular saw as well. When in doubt you should scan your wood for metal but that applies to all saws…..

  8. says:

    I’ve seen the Saw Stop before, and it has a limited application in wood working education, where you’re working with inexperienced workers (that’s where I saw it). But after you’ve spent around one hundred hours working on a table saw, you’ve incorporated the danger of the object into how you work with it.

    What I fear here is a false sense of security that builds up until bang, one day, you’re working with a saw without a Sawstop (or without a working Sawstop). Sometimes dangerous is safer. In blacksmithing, everybody starts out thinking you should wear gloves, I mean, you’re working with hot metal right? The problem is, if you touch hot metal with bare skin, you drop it instantly. If you touch it with gloves, you hold on to it for a moment, the gloves catch on fire, and your hands are toast.

    I’m not running down Sawstop – they make a fine product that really works, and reduces the risk greatly for beginners. But we can’t have everything in life Nerfifed (especially if we want to be Makers), and sometimes the solution is just to exercise caution and good judgment.

    1. says:

      I don’t want to argue with your basic point that some safety features make us more likely to cause greater accidents. I agree with that. But how do you distinguish between safety features that make our lives better and safety features that lull us into a false sense of security?

      Certainly, you have to acknowledge that your argument has been applied to safety features (like seatbelts) that are now common and undeniably a step forward.

      How can we distinguish between safety features that are real overall improvements and safety features that simply move the danger around?

    2. says:

      Well I guess when you are working in a place where danger or risks are high, you have to always have an open mind. There should have discipline and no mischief behavior because these most likely increase the risk and endanger not only you abut also other people around you. It’s a good thing this is invented.

  9. Cornflower says:

    that in the recent entries, and Makezine’s RSS scroll, that this article, “Crazy ridiculous safety saw can detect fingers and shut off”, immediately follows the “Museum of Torture Tools”?

  10. netserv666 says:

    I agree that your logic does seem to make sense , however facts don’t bear out your assumption … By far and away statistics on table saw accidents show that most severe accidents happen to experienced and seasoned woodworkers newbies rarely cut off their fingers …..

    Sorry nice try tho

  11. Jim McCorison says:

    While the gory stories are of severed fingers, hands, etc. The overwhelmingly most common injury with tablesaws are injuries caused by kickback. The SawStop does nothing to prevent them.

    I think the technology is great, and for people that want it, it is great that it is available. My biggest concern is that it will be crammed down our throat by the nanny state.

    Yes, a SawStop is comparably priced compared to other products. But then again, SawStop doesn’t have to pay 8% royalties, or purchase the cartridges from themselves. Let’s be optimistic and say that the total amount is 10% (the pessimists indicate a lot more) that gets added to the cost of a product competing with SawStop. In the retail market place, 10% is a huge amount.

    So, safety yes. But mandated safety at competition killing costs is a scary thing to consider.

  12. says:

    Maybe its because I work in orthopedics, and get to take care of the guys who have lost fingers or had fingers replanted after a run-in with a table saw, but why are people complaining that its “too safe”? I’ll draw the same comparison I did on the facebook version of this post – Airbags and antilock brakes don’t make people careless, they save lives. Covers on laser cutters save eyes. Why is it bad when things are made safer? Finger replant costs in the hundreds of thousands of dollars. Then there is the rehab, and a good chance that that particular worker is never going to do that job again, and so will need disability and/or job retraining. Losing fingers may not kill you, but it can destroy your life.

    1. Jim McCorison says:


      The gripes, at least on my part, aren’t the increased safety. It is the risk that manufacturers will feel that they _must_ incorporate these safety features in order to ward off deep-pocket style lawsuits. At what cost is a required safety feature cost justifiable. For one person, paying $200 more for a table saw and he doesn’t loose his hand, it is well worth the cost. But multiply that same $200 across the millions of table saws sold annually and what is the cost to society at large to prevent these injuries? Where do we draw the line. After all, if the goal is to prevent table saw injuries, the most certain method is an outright ban on the sales of table saws.

      As makers we should all be aware of the safety-at-any-cost mentality. There have been numerous other posts grousing about devices you can’t open and tinker with or repair. I experienced that with a heater that stopped working. The case was held together with security screws. After removing the screws I was able to replace the fuse soldered to the control board and continue using the heater instead of throwing it away. I’m certain the security screws were used because “there are no user serviceable parts inside”. Or in other words, we don’t want to be sued if somebody repairs this incorrectly and kills their family by burning down the house.

      This protect the user from themselves mentality is gradually pervading out society. If anything could have been done to prevent an accident, and it wasn’t, than the manufacturer was at fault and is held liable. The end result of this will be that dangerous tools could become more and more “protected” until they are impossible to use. Or worse, restricted and controlled. Only those that have passed a federally mandated safety training program, at whatever cost it happens to be, will be licensed to purchase or operate a given tool.

      Safety is great. But when it becomes the be all, end all, it then our threatens freedom to enjoy hobbies or activities that we wish to pursue.

      1. netserv666 says:

        Yeah I feel the same way about narcotics after all they are just mind tools , those damn government bad guys trying to protect us from ourselves ……are you complaining about torte reform or product inovation I seem to have lost sight of the topic LOL …

        By the way the Saw Stop came in the best packaging I have ever seen with excellent instructions. It is a dream to to use and set up was very accurate and easy…

        So if you really want a good saw and don’t want the safety you can turn on the safety by-pass …. It will still be one hell of a fine tool….. You can rest assured I leave my safeties engaged and even added feather boards because I am way more afraid of kick backs than anything else on a table saw …..

        1. Jim McCorison says:

          I’m not complaining about product innovation. That in itself is great. But when you have the situation where an inventor is asking for royalties many times in excess of the norm, and tries to persuade government officials that his invention should be mandatory, it begins to look more like a greed pile on than anything else.

          And yes, I think torte reform is also necessary. When people do stupid things they shouldn’t hold other people accountable. “No your honor I didn’t look before I stepped off the cross walk into a busy street. But the driver should have seen me standing on the curb and anticipated that I would step in front of him.” “Yes I know that gasoline is flammable, but the gas tank didn’t have a sticker on it telling me not to check the fuel level with a match for light.” The list is only limited by one’s imagination.

          So to summarize, product innovation is great, but don’t use it as a cudgel to reap unreasonable profits. Yes, we need torte reform so that people are expected to use at least a modicum of common sense.

          1. Jennifer Elaan says:

            As I said above, look up US Patent #3785230, filed Nov 8, 1972.

            Any sufficiently motivated manufacturer can re-invent this safety technology and avoid paying royalties to SawStop. The old patent, which is expired, spells out all the major components of a similar safety system.

            SawStop managed to refine one version of this technology to a practical level, but there are many other possibilities.

  13. David Abrams says:

    They work by spring loading a block of soft metal and dropping into the blade when contact with a [relatively] wet object is detected. You then need to throw away the old saw blade (embedded in the block) and replace both the blade and the stop mechanism. Wet wood will trigger the stop mechanism so there is a switch to disable it if you are cutting something conductive or wet.

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